1. Field of Technology
The present invention relates to an organic light emitting diode (OLED) display device and a method for driving the same, which are capable of simplifying the configuration of an overcurrent prevention circuit while preventing overcurrent generation in an image display panel, and achieving a reduction in production costs.
2. Discussion of the Related Art
Among flat panel display devices, which are an area of great interest at present, there are different types of flat panel display devices such as a liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) device, an organic light emitting diode (OLED) display device, etc. Among such flat panel display devices, the OLED display device is usefully applied to mobile communication appliances such as smartphones or tablet computers because it exhibits high luminance, and employs a low drive voltage while having an ultra-slim structure.
Such an OLED display device includes a plurality of pixels. Each pixel includes an OLED pixel including an anode, a cathode, an organic light emitting layer formed between the anode and the cathode, and a pixel circuit for independently driving the OLED pixel. The OLED display device also includes a driving control circuit for driving respective pixel circuits of the pixels.
In the OLED display device, a predetermined reference gamma voltage is sub-divided into gamma voltages for different grayscales. Using the sub-divided gamma voltages for different grayscales, digital data is converted into analog data signals (current or voltage signals). The analog data signals are supplied to respective pixel circuits, to enable an image to be displayed through the OLED pixels.
The luminance of each OLED pixel is determined by an amount of current flowing through the OLED pixel. Accordingly, when the brightness of an image to be displayed is increased, an increased amount of current flows through the OLED pixel. When the consumption of current in the OLED pixel is increased, power consumption of the OLED display panel is inevitably increased. As current consumption increases, the OLED display panel lifespan may be decreased.
In conventional cases, a frame current amount is controlled by storing image data in units of at least one frame, and setting maximum brightness in accordance with brightness degrees of the stored frame data such that an image is displayed at lower brightness than the maximum brightness.
However, the conventional frame current amount control method requires a separate memory to store frame data until digital data is modulated into an analog signal after setting of maximum brightness. For this reason, circuit configurations are complicated, and costs are increased. Furthermore, the time taken to modulate image data in accordance with maximum brightness on a per frame basis is lengthened.